1. Field of the Invention
This invention relates generally to internal combustion engine assemblies including cylinder liners, and methods of manufacturing the same.
2. Related Art
Manufacturers of internal combustion engines continuously strive to reduce the total weight of the engine, which in turn reduces fuel consumption and carbon dioxide emissions. For example, heavy duty diesel engine blocks formed of compact graphite cast iron have been designed using complex metallurgical casting processes and sophisticated and costly sculpturing of their external walls in order to reduce the total weight of the engine. However, smaller diesel engines shed greater amounts of heat than typical diesel engines. For example, the cooling needs of a typical internal combustion diesel engine amounts to about 20-25% of the heat input given off by the fuel burned, while the smaller engines typically shed even greater amounts of heat, reaching from about 25-30% of the heat input given off by the fuel burned. This amount of lost heat requires even more complex sculpturing of the internal walls of the engine block to convey coolant to the diverse parts of the cylinder liner disposed in the engine block at the appropriate rate.
In addition to the high cost, the complex wall geometry creates stagnation of pockets of fluid, which induces problems with nucleate boiling and cavitation and can be harmful to the engine. These drawbacks can be mitigated by increasing the quantity of the coolant, limiting the heat gradient of the coolant to no more than 8-10° C., and speeding up the flow of the coolant to the extent possible without cavitating the fluid. However, all of these expedients impose increased parasitic pumping losses, which are reflected in an undesirable increase in fuel consumption and carbon dioxide emissions.